1. The Nervous System
山东大学医学院 解剖教研室
李振华

2. Organizations Central nervous system (CNS) 中枢神经系统
Peripheral nervous system (PNS) 周围神经系统

3. Major Division of the Central Nervous System (CNS)
Brain 脑
Telencephalon 端脑
Diencephalon 间脑
Cerebellum 小脑
Brain stem 脑干
Midbrain 中脑
Pons 脑桥
Medulla oblongata 延髓
Spinal cord 脊髓

4. Major Division of the Peripheral Nervous System (PNS)
Cranial nerves (12 pairs) 脑神经
Spinal nerves (31 pairs) 脊神经
Visceral nerves内脏神经
Visceral sensory nerve
Visceral motor nerve
Sympathetic part 交感神经
Parasympathetic part 副交感神经

5. Cellular Organization
Neuron 神经元
Cell body 胞体
Axon 轴突
Dendrites 树突
Neuroglia －glial cell胶质细胞

6. Classification of Neurons
Structural classification
Bipolar neuron 双极神经元
has an axon and a dendrite
Pseudounipolar neuron 假单极神经元
has a central branch and a peripheral branch
Multipolar neuron 多极神经元
has an axon and two or more dendrites

7. Classification of Neurons
Functional classification
Sensory (afferent) neuron 感觉神经元
Motor (efferent) neuron 运动神经元
Association neuron 联络神经元

8. Reflex and Reflex Arc Receptor
Reflex: a reaction of the organism by the nervous system in response to a stimulus
Reflex arc: has 5 basic components
Receptor ↓
Sensory neurons
CNS
Motor neurons
Effector

9. Reflex and Reflex Arc

10. Basic Terminology in Nervous System
In the CNS
Gray matter 灰质: collection of nerve cell bodies and their dendrites, gray color during fresh condition
Cortex 皮质: the outermost layer of gray matter in cerebrum and cerebellum
White matter 白质: collection of nerve fibers, white color during fresh condition
Medulla 髓质: a central core of white matter beneath cortex of cerebrum and cerebellum

11. Basic Terminology in Nervous System
In the CNS
Nucleus 神经核: a collection ( group ) of cell bodies which have the same shape and function
Fasciculus ( tract ) 纤维束: a bundle of nerve fibers which have the same origin, termination, pathway and function
Reticular formation 网状结构: an admixture of cross-crossing fibers with larger or smaller groups of nerve cells occupying the meshes

12. Basic Terminology in Nervous System
In the PNS
Ganglion 神经节: a collection of neuronal cell bodies outside the CNS
Nerve 神经: a bundle of nerve fibers held together by connective tissue sheath

13. The Spinal Cord 脊髓
学习方法
看断面，想立体，上下串联。

14. Position of the Spinal Cord
Lies in vertebral canal
Continuous above with medulla oblongata at level of foramen magnum
Ends below at the lower border of L1 in the adult; at birth the cord ends at level of L3

16. External Features of Spinal Cord
A long cylindrical structure and slightly flattened anteroposteriorly
Two enlargements
Cervical enlargement 颈膨大 corresponds to the C4 to the T1 segments
Lumbosacral enlargement 腰骶膨大 corresponds to the L2 to the S3 segments
Conus medullaris 脊髓圆锥
Filum terminale 终丝
Cauda equina 马尾

17. External Features of Spinal Cord
Fissure and sulci
Anterior median fissure 前正中裂
Posterior median sulcus 后正中沟
Posterior median septum 后正中隔
Anterolateral sulcus 前外侧沟 －anterior (motor) roots emerge serially
Posterolateral sulcus 后外侧沟 －posterior (sensory) roots enter spinal cord, each bear a spinal ganglion which constitutes the first cell-station of the sensory nerves

18. Segments of Spinal Cord
A portion of the cord that gives rise to a pair of spinal nerve constitutes a segment.
There are 31 segments
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

19. Relationship of spinal Cord Segments to Vertebral Numbers
Spinal segments
Vertebral levels (spines)
Upper cervical region (C1~C4)
Lie opposite the corresponding vertebrae
Lower cervical and upper thoracic region (C5~T4)
One lower in number than corresponding vertebrae
Middle thoracic region (T5~T8)
Two lower in number than corresponding vertebrae
Lower thoracic region (T9~T12)
Three lower in number than corresponding vertebrae
Lumber segments
T10~T12
Sacral and coccygeal segments L1

20. Relationship of spinal Cord Segments to Vertebral Numbers
Spinal segments
Vertebral levels (spines)
Upper cervical region (C1~C4)
= C1 ~ C4
Lower cervical and upper thoracic region (C5~T4)
－1 = C4 ~ T3
Middle thoracic region (T5~T8)
－2 = T3 ~ T6
Lower thoracic region (T9~T12)
－3 = T6 ~ T9
Lumber segments
= T10 ~ T12
Sacral and coccygeal segments
= L1

21. Structure of Spinal Cord
Gray matter 灰质
White matter 白质
Central canal 中央管

22. Gray Matter of Spinal Cord
Anterior horn (column) 前角（柱）
Posterior horn (column)后角（柱）
Lateral horn (column) 侧角（柱） is present in the thoracic and upper lumber segments of the cord (T1-L3)
Intermediate zone 中间带
Anterior gray commissures 灰质前连合
Posterior gray commissures 灰质后连合

23. Gray Matter of Spinal Cord
Posterior horn (column):
Marginal layer 缘层 （后角边缘核）
Substantia gelatinosa 胶状质
Situated at the apex of posterior horn throughout the length of spinal cord
Concerns the sensations of pain and temperature
Nucleus proprius 后角固有核
Situated anterior to the substantia gelationnosa throughout the length of spinal cord
Receives fibers that are associated with the senses
Nucleus thoracicus 胸核
Situated at the base of posterior horn and extending from segments C8~L3
Associated with proprioceptive endings

24. Gray Matter of Spinal Cord
Intermediate zone
Intermediaolateral nucleus 中间外侧核 (lateral horn)
Extents from segments T1~L3,
Containing sympathetic preganglionic neurons
Sacral parasympathetic nucleus 骶副交感核
Extents from segments S2~S4,
Containing parasympathetic preganglionic neurons
Intermediomedial nucleus 中间内侧核
Throughout the length of spinal cord
Associated with receiving viscera afferent information

25. Gray Matter of Spinal Cord
Anterior horn (column):
Two kinds of motor neurons
α-motor neuron: large multipolar neuron, innervates skeletal muscles, producing contraction of muscles
γ-motor neuron: smaller multipolar neuron, innervates intrafusal muscle fibers of neuromuscular spindles, regulating muscular tonus
Interneuron —Renshaw’s cell: negative feedback mechanism
Two groups of nuclei
Medial nuclear group: present in most segments of spinal cord, innervating axial muscles
Lateral nuclear group: present only in cervical and lumbosacral enlargements, innervating limb muscles

26. Rexed’s lamina 板层 Posterior horn is formed by lamina Ⅰ to Ⅵ；
Intermediate zone corresponding to lamina Ⅶ；
Anterior horn is composed laminae Ⅷ and Ⅸ；
lamina Ⅹ is the gray matter surrounding the central canal.

27. Important Subdivision of Spinal Cord Gray Matter
Region
Lamina
Nucleus
Posterior horn Ⅰ
Marginal layer Ⅱ
Substantia gelatinosa
Ⅲ, Ⅳ
Nucleus proprius
Intermediate zone Ⅶ
Nucleus thoracicus (C8~L3)
Intermediolateral nucleus (T1~L3)
Sacral parasympathetic nucleus (S2~S4)
Intermediomedial nucleus
Anterior horn Ⅸ
Motor neuron

28. White Matter of Spinal Cord
White matter contains three kinds of fibers: ascending, descending, and fasciculus proprius
Posterior funiculus后索
Lateral funiculus
外侧索
Anterior white commissure白质前连合
Anterior funiculus 前索

29. Ascending Tracts Fasciculus gracilis（薄束） Fasciculus cuneatus （楔束）
Posterior spinocerebellar tract
（脊髓小脑后束）
Anterior spinocerebellar tract
（脊髓小脑前束）
Spinothalamic tract
（脊髓丘脑束）

30. Fasciculus cuneatus
Fasciculus gracilis

31. Spinothalamic tract

32. Ascending tracts Tract Funiculus Function Site of origin Termination
Fasciculus gracilis
Spinal ganglia below segment T5
Posterior
Gracile nucleus
Conscious proprioceptive (vibratory sense, and muscle joint sense) and fine touch sensation of trunk and limbs
Fasciculus cuneatus
Spinal ganglia above segment T4
Cuneate nucleus
Posterior spinocerebellar
Homolateral nucleus thoracicus
Lateral
Cerebellum
Unconscious proprioception from lower limb and lower portion of trunk
Anterior spinocerebellar
Contralateral Laminae
Ⅴ~Ⅶ
Spinothalamic
Laminae Ⅰ, Ⅳ~Ⅶ
Lateral and anterior
Dorsal thalamus
Pain, temperature and crude touch sensation of trunk and limbs

33. Descending Tracts Lateral corticospinal tract （皮质脊髓侧束）
Fasciculus proprius （固有束）
Rubrospinal tract
（红核脊髓束）
Medial longitudinal fasciculus （内侧纵束）
Reticulospinal tract
（网状脊髓束）
Vestibulospinal tract（前庭脊髓束）
Tectospinal tract（顶盖脊髓束）
Anterior corticospinal tract （皮质脊髓前束）

35. Descending tracts Tract Site of origin Funiculus Termination Function
Lateral corticospinal
Cerebral cortex
Lateral
Laminae
Ⅳ~Ⅸ
anterior horn
Voluntary movement
Anterior corticospinal
Anterior
Rubrospinal
Red nucleus
Ⅴ~Ⅶ
Facilitates activity of flexor muscles
Vestibulospinal
Homolateral vestibular nuclei
Ⅶ~Ⅷ
Facilitates activity of extensor muscles
Reticulospinal
Reticular formation
Anterior and lateral
Medial longitudinal fasciculus
Vestibular nuclei
Coordinate neck with eye movement
Tectospinal
Superior colliculus
Ⅵ~Ⅷ
Fasciculus proprius
Spinal cord
Anterior, lateral and posterior
Intrinsic reflex mechanism of spinal cord

37. Main functions of spinal cord
Conduction of excitations
Reflex activity